Random under extrusion lines on my Ender 3 V3 using Simplify3D

[markhughes]

Hello everyone, I am Skyler and just joined this forum. I have been using Simplify3D for a few weeks with my Ender 3 V3 and noticed a strange problem that I cannot solve. Every few layers, there is a thin line across the surface that looks slightly under extruded, as if the filament flow drops for a short moment.
I already cleaned the nozzle, checked the filament path, and replaced the PTFE tube. I also tested different coasting distances and adjusted the extrusion multiplier, but the issue keeps showing up on smooth walls. When I use Cura, the same model prints cleanly, so I suspect something in my Simplify3D setup.
Has anyone experienced this type of layer inconsistency before? Could it be related to retraction during wipe, or maybe a timing issue with layer transitions? Any ideas or profile tips would be a huge help.

[S3D-Jason]

Can you post a photo showing the defects you are seeing?